1. Field of the Invention
The present invention relates to a filtering device comprising a rising pipe basically shaped into a cylinder having a drain port at its upper end and placed within a box-like basin to vertically extend, and a cylinderical porous air injecting member contained within the rising pipe at its lower portion in a connected relationship to a pressurized air source to develop an upward flow of water within the rising pipe.
2. Description of the Prior Art
In such conventional filtering devices, the rising pipe is commonly placed within the basin at a distance spaced from the inner surface of the basin.
However, the exsistence of a space between the rising pipe and the inner surface of the basin may permit aquarium fish cultivated within the basin to enter that space, so that they are sandwiched between a filter case and the inner surface of the basin to become motionless.